Since the end of May, the pope's former butler, Paolo Gabriele, has been detained in a 35-square-metre cell at the Vatican, with a window but no TV.
Using the code name "Maria," he allegedly smuggled faxes and letters out of the pope's private quarters.
But it remains unclear who was directing him to do so, reports Der Spiegel.
Even with Gabriele's arrest, the leak still hasn't been plugged. More documents were released to the public last week, documents intended primarily to damage two close associates of Pope Benedict XVI: his private secretary, Georg Gänswein, and Cardinal Secretary of State Tarcisio Bertone, the Vatican's top administrator.
According to one document, "hundreds" of other secret documents would be published if Gänswein and Bertone weren't "kicked out of the Vatican."
"This is blackmail," says Vatican expert Marco Politi. "It's like threatening total war."
Fear is running rampant in the Curia, where the mood has rarely been this miserable. It's as if someone had poked a stick into a beehive.
Men wearing purple robes are rushing around, hectically monitoring correspondence. No one trusts anyone anymore, and some even hesitate to communicate by phone.
It all began in the accursed seventh year of the papacy of Benedict XVI, with striking parallels to the latter part of Pope John Paul II's papacy.
The same complaints about poor leadership and internal divisions are being aired outside the Vatican's walls, while the pope himself seems exhausted and no longer able to exert his power.
Joseph Ratzinger turned 85 in April. This makes him the oldest pope in 109 years, and one of the few popes who have exercised what Benedict has called this "enormous" office at such an advanced age.
Of course, he is still enviably fit, both mentally and physically, especially compared to his predecessor in his later years. But speaking has become unmistakably more difficult for Benedict than at the beginning of his papacy, and it's hard to miss that his movements have become stiff and cautious.
He recently told a visitor that his old piano hardly gets any use anymore. Playing it requires practice, he added, but he doesn't have any time for that. He prefers to continue working on the last part of his series on Jesus, which he wants to finish before dying.
These days, it isn't difficult to find clerics at the Vatican who are willing to talk, provided their identities remain anonymous.
The monsignor who finds his way to a restaurant near Piazza Santa Maria in Rome's Trastevere neighborhood one evening worked closely with Ratzinger in the CDF for years.
But even before the waiter arrives with water and wine, the monsignor delivers his verdict on Ratzinger's papacy: "The pope doesn't fully exercise his office!" In his view, instead of having things under control, they control him.
The pope isn't interested in daily affairs at the Vatican, says the anonymous monsignor. Still, this is not exactly unprecedented, as his predecessor also neglected the Curia. While the Polish pope spent a lot of time traveling, his German successor is apparently happiest while poring over books and writing speeches.
"He simply isn't taking matters into his own hands," the monsignor says. In essence, he adds, the pope faces a different power in Rome -- and one he hasn't take command of.